Sheets or tiles in agglomerate material presenting an internal reinforcement structure are frequently used for laying so-called raised or floating floors in which the sheets or tiles are positioned on top of an appropriate wire grid which is raised with respect to the ground thus making it possible to obtain a hollow space with a predetermined height, allowing the laying of large quantities of electrical and/or hydraulic ducting and their easy maintenance or modification.
While on one hand raised or floating floors present considerable advantages, including those described above, on the other they involve a series of drawbacks which limit their construction and use or make them difficult.
A first drawback presented by raised or floating floors made from composite material is due to the fact that these floors are usually electrically ground-insulated.
This implies an unfavourable accumulation of electrostatic charges on objects which are present on or which move on this floor, an effect which is unacceptable for numerous precision electronic devices but which may be even more simply disadvantageous if these electrostatic discharges involve the people who walk across the floor.
A further limitation usually involved in the construction of raised or floating floors consists of the fact that the sheets must directly support the weight of considerable loads and must therefore be fairly thick in order to withstand maximum breaking loads in compliance with safety regulations.
All this inevitably means not only great structural and working limitations but also high costs and lengthy and difficult laying times for these floors.
The Italian document VR94A000068 describes a procedure for the production of sheets made from agglomerate material comprising a series of processing stages, specifically:                an initial stage consisting of the crushing of the various materials making up the agglomerate;        a second stage consisting of the mixing of the crushed materials in order to obtain a product which is as homogeneous as possible, during which the binding resins are added;        a third stage consisting of the pressing and compacting of the agglomerate during which the required shape is obtained and in which a wire or fibre mesh is buried, this being formed by a plurality of wires arranged according to a predetermined layout and whose ends are situated at the same level as or protrude beyond the lower surface of the sheet;        a fourth stage in which the sheet is hardened at a predetermined temperature;        a fifth stage in which at least one side of the sheet is smoothed and polished;        a sixth stage in which the sheet is cut to size, chamfered, gauged and flared, followed by unloading of the end products.        
A procedure such as the one described above makes it possible to obtain sheets made from agglomerate material, with precisely predetermined lengths, widths and thicknesses, and which is performed in a continuous process on a specially designed plant.
In spite of the presence of the wire-mesh consisting of wires as described above, the previously mentioned disadvantages are still present, particularly as regards the electrostatic charge.
In fact, during the hardening stage the resin envelops the metal surface of the wires forming the reinforcement mesh, creating an insulation film which does not permit effective discharge of the accumulated electrostatic charge.
Document U.S. Pat. No. 4,640,854 discloses a composite plate for double floors comprising a pan-shaped wrapper for receiving therein a flowable and hardenable filler material. The wrapper comprises a plurality of downwardly extending projecting blocks containing the filler material.
Documents U.S. Pat. Nos. 4,833,845 and 5,057,355 disclose a metallic shallow pan serving for the production of a self-supporting composite plate, wherein the pan forms the outside wrapper for a filler with high compression resistance such as anhydrite.